The present invention relates to a modular stent-graft system for delivery into a blood vessel of a patient to be treated.
Vascular implants of this type are known in the prior art, for example from DE 103 37 739.5.
In general, it is known to utilize intraluminal vascular implants, which are also referred to as endovascular stents or stent grafts, for treating weakened, injured, torn, or aneurysmal vessels. For this purpose, a vascular implant or stent graft is released at the diseased or injured site of the vessel, and restores the functionality of the original vessel and/or supports the remaining vascular integrity.
In this case, an aneurysm is understood to mean an expansion or bulging of an arterial blood vessel as a result of congenital or acquired changes in the wall. The bulging can involve the vascular wall in entirety or, as in the case of a so-called false aneurysm or so-called dissection, blood from the lumen of the vessel collects between the layers of the vascular wall and separates said layers. In the advanced stage of the non-treatment of an aneurysm, the artery can rupture, with the consequence that the patient bleeds internally.
The self-expanding vascular implants utilized for treating aneurysms of this type generally consist of a hollow cylindrical metal frame or scaffold, the lateral face of which is covered by a textile foil or polymer foil, and therefore a hollow cylindrical body results. For implantation, the vascular implant is radially compressed, and therefore its cross-sectional area is substantially reduced. With the aid of a delivery system, the vascular implant is then brought into the region of the aneurysm, where it is released. Due to the spring action of the metal frame/scaffold, the vascular implant expands back into its original shape and thereby deploys its lateral face which lodges internally in the blood vessel, proximally and distally to the aneurysm. In this way, the blood now flows through the vascular implant and a further strain on the bulge is prevented.
The metal frame of such vascular implants usually consists of, for example, a wire mesh or so-called stent springs which are successively arranged and spaced apart from one another over its longitudinal axis and which circumferentially meander, and which are optionally interconnected via connection supports made from wire, or which are indirectly interconnected merely via the implant material. The wire mesh or the stent springs are usually made from a shape memory material, usually Nitinol, whereby, after insertion into a vessel in order to be released, the stent springs transition back into the expanded state and thereby “deploy” the vascular implant.
Aneurysms frequently occur in the region of the abdominal aorta (Aorta abdominalis) or the thoracic aorta (Aorta thoracica). In order to treat aneurysms in the abdominal aorta or the thoracic aorta, it is already known to stabilize the artery via implantation of a stent to the extent that a rupture of the vessel is avoided.
Aneurysms can also occur, however, in the so-called ascending branch of the aorta (Aorta ascendens). The ascending branch of the aorta is directly connected to the heart. Proceeding from the root of the aorta (Sinus aortae), the ascending branch extends, in a slightly curved shape, upward and away from the heart and, there, transitions into the aortic arch (Arcus aortae). In the region of the aortic arch, the head vessels branch off, e.g., the left common carotid artery and the right common carotid artery. The aortic arch extends in a curve through approximately 180° with a very narrow radius and connects the ascending branch of the aorta to the thoracic artery and, further along, to the abdominal artery.
It is important—not only in the region of the aortic arch—to avoid blocking lateral vessels that branch off from main vessels by the positioning of the vascular implant, and therefore many vascular implants have open zones or so-called fenestrations, via which lateral branches, which branch off from the vascular implant and protrude into the lateral vessels, can be inserted and fixed on the vascular implant.
An aneurysm or a dissection in the ascending branch of the aorta is treated, even today, in an invasive open surgical procedure. So far, such an operation regularly necessitates two major surgeries carried out at different times, and is a very large and complex and, therefore, dangerous surgical operation, since a hypothermic perfusion, i.e., an artificial, cold, extracorporeal circulation, or a hypothermic circulatory arrest must be carried out not only on the heart, but also on the brain and the abdominal organs of the patient. Only a few cardiac surgeons at experienced hospitals are familiar with such a surgical procedure.
There is still a great demand for stent systems and stent-graft systems, or vascular implants, with the aid of which the above-described surgical procedure could be simplified and shortened.